SSc biomarkers detection in the secretome of TGF1-activated primary human lung fibroblasts.

TGFβ1 is a profibrotic mediator that contributes to a broad spectrum of pathologies, including pulmonary fibrosis (PF). However, the secretome of TGFβ1-stimulated primary human normal lung (NL) fibroblasts has not been well characterized. Using fluorescent 2-dimensional gel electrophoresis (2D-PAGE) and differential gel electrophoresis (DIGE), we identified 37 differentially secreted proteins in the conditioned media of TGFβ1-activated NL fibroblasts and generated a protein-protein association network of the TGFβ1 secretome using STRING. Functional enrichment revealed that biological processes and pathways characteristics of PF were enriched. Using the DrugBank database, we determined that 32 of the secreted proteins are targets of known experimental, investigational and approved drugs. Additionally, by comparing the TGFβ1 secretome of NL fibroblasts to proteomic biomarkers from biological fluids of systemic sclerosis (SSc) patients, we identified 11 overlapping proteins. Together our data validate the TGFβ1-induced secretome of NL fibroblasts as a valid in vitro model that reflects SSc biomarkers and identifies potential therapeutic targets for SSc-PF.